Metaheuristic- and Statistical-Based Sampling in Optimization

Author(s):  
Yoel Tenne

Modern engineering often uses computer simulations as a partial substitute to real-world experiments. As such simulations are often computationally intensive, metamodels, which are numerical approximations of the simulation, are often used. Optimization frameworks which use metamodels require an initial sample of points to initiate the main optimization process. Two main approaches for generating the initial sample are the ‘design of experiments' method which is statistically based, and the more recent metaheuristic-based sampling which uses a metaheuristic or a computational intelligence algorithm. Since the initial sample can have a strong impact on the overall optimization search and since the two sampling approaches operate based only widely different mechanisms this study analyzes the impact of these two approaches on the overall search effectiveness in an extensive set of numerical experiments which covers a wide variety of scenarios. A detailed analysis is then presented which highlights which method was the most beneficial to the search depending on the problem settings.

2017 ◽  
Vol 27 (1) ◽  
pp. 105-118 ◽  
Author(s):  
Yoel Tenne

Abstract Modern engineering design optimization often uses computer simulations to evaluate candidate designs. For some of these designs the simulation can fail for an unknown reason, which in turn may hamper the optimization process. To handle such scenarios more effectively, this study proposes the integration of classifiers, borrowed from the domain of machine learning, into the optimization process. Several implementations of the proposed approach are described. An extensive set of numerical experiments shows that the proposed approach improves search effectiveness.


Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1607-P
Author(s):  
MAYU HAYASHI ◽  
KATSUTARO MORINO ◽  
KAYO HARADA ◽  
MIKI ISHIKAWA ◽  
ITSUKO MIYAZAWA ◽  
...  

2020 ◽  
Author(s):  
M Testori ◽  
M Kempf ◽  
RB Hoyle ◽  
Hedwig Eisenbarth

© 2019 Hogrefe Publishing. Personality traits have been long recognized to have a strong impact on human decision-making. In this study, a sample of 314 participants took part in an online game to investigate the impact of psychopathic traits on cooperative behavior in an iterated Prisoner's dilemma game. We found that disinhibition decreased the maintenance of cooperation in successive plays, but had no effect on moving toward cooperation after a previous defection or on the overall level of cooperation over rounds. Furthermore, our results underline the crucial importance of a good model selection procedure, showing how a poor choice of statistical model can provide misleading results.


Author(s):  
Md. Ziaul Haque

The tourism sector is experiencing numerous challenges as a result of the global economic crisis. After a significant contraction in 2009, tourism rebounded strongly  in  2010  and  in  2011  the  international  tourist  arrivals  and  receipts  are projected to increase substantially. The Tourism industry is expected to show a sustained recovery in 2012. The crisis has particularly strong impact and slightly negative consequences in Bangladesh. The country is undergoing a political crisis, as well, and it seems that the forthcoming elections may be the only solution for the restoration of stability and social peace.  In addition, tourism can be the driving force behind Bangladesh economic recovery. However, for its achievement the country’s policy makers should take several measures towards restructuring and improving the sector. These measures include: enhancement of alternative forms of tourism; environmental protection; creation of quality infrastructure; and boost of competitiveness through a tourism product that offers value for money


Author(s):  
Md. Ziaul Haque

The tourism sector is experiencing numerous challenges as a result of the global economic crisis. After a significant contraction in 2009, tourism rebounded strongly  in  2010  and  in  2011  the  international  tourist  arrivals  and  receipts  are projected to increase substantially. The Tourism industry is expected to show a sustained recovery in 2012. The crisis has particularly strong impact and slightly negative consequences in Bangladesh. The country is undergoing a political crisis, as well, and it seems that the forthcoming elections may be the only solution for the restoration of stability and social peace.  In addition, tourism can be the driving force behind Bangladesh economic recovery. However, for its achievement the country’s policy makers should take several measures towards restructuring and improving the sector. These measures include: enhancement of alternative forms of tourism; environmental protection; creation of quality infrastructure; and boost of competitiveness through a tourism product that offers value for money


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 839.2-840
Author(s):  
C. Vesel ◽  
A. Morton ◽  
M. Francis-Sedlak ◽  
B. Lamoreaux

Background:NHANES data indicate that approximately 9.2 million Americans have gout,1 with a small subset having uncontrolled disease.2 Pegloticase is a PEGylated recombinant uricase enzyme indicated for treating uncontrolled gout that markedly reduces serum uric acid levels (sUA)3 and resolves tophi in treatment responders.4 Despite pegloticase availability in the US for many years, real world demographics of pegloticase users in the treatment of uncontrolled gout have not been previously reported in a population-based cohort.Objectives:This study utilized a large US claims database to examine demographics and co-morbidities of uncontrolled gout patients treated with pegloticase. Kidney function before and after pegloticase treatment and concomitant therapy with immunomodulators were also examined.Methods:The TriNetX Diamond database includes de-identified data from 4.3 million US patients with gout (as of September 2019), including demographics, medical diagnoses, laboratory values, procedures (e.g. infusions, surgeries), and pharmacy data. Patients who had received ≥1 pegloticase infusion were included in these analyses. The number of infusions was evaluated for a subgroup of patients who were in the database ≥3 months before and ≥2 years after the first pegloticase infusion (i.e. first infusion prior to September 2017) to ensure only complete courses of therapy were captured. In this subpopulation, kidney function before and after pegloticase therapy was examined, along with the presence of immunomodulation prescriptions (methotrexate, mycophenolate mofetil, azathioprine, leflunomide) within 60 days prior to and 14 days after the first pegloticase infusion.Results:1494 patients treated with pegloticase were identified. Patients were 63.1 ± 14.0 years of age (range: 23–91), mostly male (82%), and white (76%). Mean sUA prior to pegloticase was 8.7 ± 2.4 mg/dL (n=50), indicating uncontrolled gout in the identified population. The most commonly reported comorbidities were chronic kidney disease (CKD, 48%), essential hypertension (71%), type 2 diabetes (39%), and cardiovascular disease (38%), similar to pegloticase pivotal Phase 3 trial populations. In patients with pre-therapy kidney function measures (n=134), pre-treatment eGFR averaged 61.2 ± 25.7 ml/min/1.73 m2, with 44% having Stage 3-5 CKD. In patients with complete therapy course capture and pre- and post-therapy eGFR measures (n=48), kidney function remained stable (change in eGFR: -2.9 ± 18.2 ml/min/1.73 m2) and CKD stage remained the same or improved in 81% of patients. In 791 patients with complete treatment course capture, patients had received 8.7 ± 13.8 infusions (median: 3, IQR: 2-10). Of these, 189 (24%) patients received only 1 pegloticase infusion and 173 (22%) received ≥12 infusions. As the data cut-off for this analysis pre-dated emerging data on the use of immunomodulation as co-therapy, only 19 of 791 (2%) patients received immunomodulation co-therapy with pegloticase.Conclusion:This relatively large group of patients with uncontrolled gout treated with pegloticase had similar patient characteristics of those studied in the phase 3 randomized clinical trials. Patients with uncontrolled gout are significantly burdened with systemic co-morbid diseases. The majority of patients had stable or improved kidney function following pegloticase treatment. As these results reflect patients initiating treatment prior to 2018, before co-treatment with immunomodulation was introduced, this cohort only included a small percentage of patients who were co-treated with an immunomodulator. Future studies using more current datasets are needed to evaluate real world outcomes in patients treated with pegloticase/immunomodulator co-therapy and to evaluate the impact of systemic co-morbid diseases.References:[1]Chen-Xu M, et al. Arthritis Rheumatol 2019 71:991-999.[2]Fels E, Sundy JS. Curr Opin Rheumatol 2008;20:198-202.[3]Sundy J, et al. JAMA 2011;306:711-720.[4]Mandell BF, et al. Arthritis Res Ther 2018;20:286.Disclosure of Interests:Claudia Vesel Shareholder of: Horizon Therapeutics plc, Employee of: Horizon Therapeutics plc, Allan Morton Speakers bureau: Sanofi, Amgen, and Horizon, Megan Francis-Sedlak Shareholder of: Horizon Therapeutics plc, Employee of: Horizon Therapeutics plc, Brian LaMoreaux Shareholder of: Horizon Therapeutics plc, Employee of: Horizon Therapeutics plc.


2020 ◽  
Vol 36 (S1) ◽  
pp. 37-37
Author(s):  
Americo Cicchetti ◽  
Rossella Di Bidino ◽  
Entela Xoxi ◽  
Irene Luccarini ◽  
Alessia Brigido

IntroductionDifferent value frameworks (VFs) have been proposed in order to translate available evidence on risk-benefit profiles of new treatments into Pricing & Reimbursement (P&R) decisions. However limited evidence is available on the impact of their implementation. It's relevant to distinguish among VFs proposed by scientific societies and providers, which usually are applicable to all treatments, and VFs elaborated by regulatory agencies and health technology assessment (HTA), which focused on specific therapeutic areas. Such heterogeneity in VFs has significant implications in terms of value dimension considered and criteria adopted to define or support a price decision.MethodsA literature research was conducted to identify already proposed or adopted VF for onco-hematology treatments. Both scientific and grey literature were investigated. Then, an ad hoc data collection was conducted for multiple myeloma; breast, prostate and urothelial cancer; and Non Small Cell Lung Cancer (NSCLC) therapies. Pharmaceutical products authorized by European Medicines Agency from January 2014 till December 2019 were identified. Primary sources of data were European Public Assessment Reports and P&R decision taken by the Italian Medicines Agency (AIFA) till September 2019.ResultsThe analysis allowed to define a taxonomy to distinguish categories of VF relevant to onco-hematological treatments. We identified the “real-world” VF that emerged given past P&R decisions taken at the Italian level. Data was collected both for clinical and economical outcomes/indicators, as well as decisions taken on innovativeness of therapies. Relevant differences emerge between the real world value framework and the one that should be applied given the normative framework of the Italian Health System.ConclusionsThe value framework that emerged from the analysis addressed issues of specific aspects of onco-hematological treatments which emerged during an ad hoc analysis conducted on treatment authorized in the last 5 years. The perspective adopted to elaborate the VF was the one of an HTA agency responsible for P&R decisions at a national level. Furthermore, comparing a real-world value framework with the one based on the general criteria defined by the national legislation, our analysis allowed identification of the most critical point of the current national P&R process in terms ofsustainability of current and future therapies as advance therapies and agnostic-tumor therapies.


2021 ◽  
Vol 8 (1) ◽  
pp. e000840
Author(s):  
Lianne Parkin ◽  
Sheila Williams ◽  
David Barson ◽  
Katrina Sharples ◽  
Simon Horsburgh ◽  
...  

BackgroundCardiovascular comorbidity is common among patients with chronic obstructive pulmonary disease (COPD) and there is concern that long-acting bronchodilators (long-acting muscarinic antagonists (LAMAs) and long-acting beta2 agonists (LABAs)) may further increase the risk of acute coronary events. Information about the impact of treatment intensification on acute coronary syndrome (ACS) risk in real-world settings is limited. We undertook a nationwide nested case–control study to estimate the risk of ACS in users of both a LAMA and a LABA relative to users of a LAMA.MethodsWe used routinely collected national health and pharmaceutical dispensing data to establish a cohort of patients aged >45 years who initiated long-acting bronchodilator therapy for COPD between 1 February 2006 and 30 December 2013. Fatal and non-fatal ACS events during follow-up were identified using hospital discharge and mortality records. For each case we used risk set sampling to randomly select up to 10 controls, matched by date of birth, sex, date of cohort entry (first LAMA and/or LABA dispensing), and COPD severity.ResultsFrom the cohort (n=83 417), we identified 5399 ACS cases during 281 292 person-years of follow-up. Compared with current use of LAMA therapy, current use of LAMA and LABA dual therapy was associated with a higher risk of ACS (OR 1.28 (95% CI 1.13 to 1.44)). The OR in an analysis restricted to fatal cases was 1.46 (95% CI 1.12 to 1.91).ConclusionIn real-world clinical practice, use of two versus one long-acting bronchodilator by people with COPD is associated with a higher risk of ACS.


2016 ◽  
Vol 28 (8) ◽  
pp. 1448-1464 ◽  
Author(s):  
Örjan Åkerborg ◽  
Andrea Lang ◽  
Anders Wimo ◽  
Anders Sköldunger ◽  
Laura Fratiglioni ◽  
...  

Objective: To estimate the cost of dementia care and its relation to dependence. Method: Disease severity and health care resource utilization was retrieved from the Swedish National Study on Aging and Care. Informal care was assessed with the Resource Utilization in Dementia instrument. A path model investigates the relationship between annual cost of care and dependence, cognitive ability, functioning, neuropsychiatric symptoms, and comorbidities. Results: Average annual cost among patients diagnosed with dementia was €43,259, primarily incurred by accommodation. Resource use, that is, institutional care, community care, and accommodation, and corresponding costs increased significantly by increasing dependency. Path analysis showed that cognitive ability, functioning, and neuropsychiatric symptoms were significantly correlated with dependence, which in turn had a strong impact on annual cost. Discussion: This study confirms that cost of dementia care increases with dependence and that the impact of other disease indicators is mainly mediated by dependence.


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